Bring back python27 checks for fuel-specs
Bring back python27 checks for fuel-specs

gate-fuel-specs-python27 job was disabled by mistake in
https://review.openstack.org/#/c/247471/

Change-Id: Idb26539f24797138333dfc7e06d717c76a6c5742
Related-Bug: #1524702

dongwenjuan/project-config,dongwenjuan/project-config,Tesora/tesora-project-config,noorul/os-project-config,openstack-infra/project-config,noorul/os-project-config,Tesora/tesora-project-config,openstack-infra/project-config